On Fri, Sep 28, 2012 at 02:51:03PM +0200, Sasha Levin wrote: > Hi all, > > While fuzzing with trinity inside a KVM tools guest with the latest > linux-next kernel, I've stumbled on the following during boot: > > [ 199.224369] WARNING: at kernel/rcutree.c:513 > rcu_eqs_exit_common+0x4a/0x3a0() > [ 199.225307] Pid: 1, comm: init Tainted: G W > 3.6.0-rc7-next-20120928-sasha-00001-g8b2d05d-dirty #13 > [ 199.226611] Call Trace: > [ 199.226951] [<ffffffff811c8d1a>] ? rcu_eqs_exit_common+0x4a/0x3a0 > [ 199.227773] [<ffffffff81108e36>] warn_slowpath_common+0x86/0xb0 > [ 199.228572] [<ffffffff81108f25>] warn_slowpath_null+0x15/0x20 > [ 199.229348] [<ffffffff811c8d1a>] rcu_eqs_exit_common+0x4a/0x3a0 > [ 199.230037] [<ffffffff8117f267>] ? __lock_acquire+0x1c37/0x1ca0 > [ 199.230037] [<ffffffff811c936c>] rcu_eqs_exit+0x9c/0xb0 > [ 199.230037] [<ffffffff811c940c>] rcu_user_exit+0x8c/0xf0 > [ 199.230037] [<ffffffff810a98bb>] do_page_fault+0x1b/0x40 > [ 199.230037] [<ffffffff810a2a90>] do_async_page_fault+0x30/0xa0 > [ 199.230037] [<ffffffff83a3eea8>] async_page_fault+0x28/0x30 > [ 199.230037] [<ffffffff819f357b>] ? debug_object_activate+0x6b/0x1b0 > [ 199.230037] [<ffffffff819f3586>] ? debug_object_activate+0x76/0x1b0 > [ 199.230037] [<ffffffff8111af13>] ? lock_timer_base.isra.19+0x33/0x70 > [ 199.230037] [<ffffffff8111d45f>] mod_timer_pinned+0x9f/0x260 > [ 199.230037] [<ffffffff811c5ff4>] rcu_eqs_enter_common+0x894/0x970 > [ 199.230037] [<ffffffff839dc2ac>] ? init_post+0x75/0xc8 > [ 199.230037] [<ffffffff85abfed5>] ? kernel_init+0x1e1/0x1e1 > [ 199.230037] [<ffffffff811c63df>] rcu_eqs_enter+0xaf/0xc0 > [ 199.230037] [<ffffffff811c64c5>] rcu_user_enter+0xd5/0x140 > [ 199.230037] [<ffffffff8107d0fd>] syscall_trace_leave+0xfd/0x150 > [ 199.230037] [<ffffffff83a3f7af>] int_check_syscall_exit_work+0x34/0x3d > [ 199.230037] ---[ end trace a582c3a264d5bd1a ]---
Ok, we can't decently protect against any kind of exception messing up everything in the middle of RCU APIs anyway. The only solution is to find out what cause this page fault in mod_timer_pinned() and work around that. Anybody, an idea? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
